Tire having bead wires tangent to one another

ABSTRACT

A tubeless radial truck tire is formed with an assembly of three bead wires in each bead around which the ends of the carcass ply or plies are wound. The bead wires are braided and of circular cross section and in each bead each bead wire is tangent to the other two.

D United States Patent 1191 1111 3,736,974

LeJeune 1 1 June 5, 1973 [54] TIRE HAVING BEAD WIRES TANGENT [56]References Cited To ONE ANOTHER UNITED STATES PATENTS [75] Dame Lemmeclermom'Ferrand 1,147,032 7/1915 McNau11 ..152/362 R France 1,686,15510/1928 Hopkins 1,715,302 5/1929 Michelin [73] Assgnee Compagme, 'l2,423,995 7 1947 Reynolds ..152/362 R ments Michelin, raison socialeMichelin 8: Cie, Clermont-Ferrand FOREIGN PATENTS OR APPLICATIONS France1,215,793 4 1960 France ..l52/362 R [22] Filed: Mar. 10, 1971 1,465,5561/1967 France..... ...152/362 R 1,418,887 10/1965 France 152/362 R 21Appl. No.: 122,934

Primary ExaminerDrayton E. Hoffman Assistant ExaminerRobert Saifer [30]Foreign Apphcamm Pnomy Data Attorney-Brumbaugh, Graves, Donphue &Raymond Mar. 13, 1970 France ..7009583 [57] ABSTRACT [52] US. Cl...l52/362 R, 245/1.5 A tubeless radial truck tire is formed with anassembly [5]] Int. Cl ..B60c 15/04 of three bead wires in each beadaround which the [58] Field of Search ..152/362 R; 245/1.5' ends of thecarcass ply or plies are wound. The head wires are braided and ofcircular cross section and in each bead each bead wire is tangent to theother two.

10 Claims, 9 Drawing Figures Patented June 5, 1973 2 Sheets-Sheet 1INVENTOR.

DANIEL LEJEUNE his A TTORNE Y5 Patented June 5, 1973 2 Sheets-Sheet 2INVENTOR. DANIEL LEJEUNE A TTORNEYS TIRE HAVING BEAD WIRES TANGENT TOONE ANOTHER BACKGROUND OF THE INVENTION This invention relates to tiresand, more particularly, to novel and highly-effective tubeless tireshaving improved bead wires. The invention is applicable especially, butnot exclusively, to radial tubeless truck tires intended to be used withrims the bead seats of which are inclined at a given angle-for examplelto the axis of the rim.

Tires for automotive vehicles such as trucks and the like are providedin each of their beads with one or more circumferential steel beadwires. The function of these bead wires is to make the beadssufficiently inextensible for the tire to be retained on the rim, aswell as. to facilitate the anchoring of the carcass plies. For thisreason a single bead wire per bead is generally used when the carcass ofthe tire is made of a single ply or of a small number of plies. On theother hand, several bead wires per bead are used when the carcass iscomposed of a large number of plies, each bead wire serving to anchor aseparate group of plies.

Two types of bead wires are currently used, namely so-called braidedbead wires and so-called package bead wires.

Braided bead wires are formed of: (l) a circular core formed of a singlesteel wire the ends of which have been welded together to form a ring;(2) a layer arranged around the core and formed from a steel wirehelically wound on the core so as to form a plurality of helices whichare juxtaposed and which cover the entirecore, the two ends of the wirebeing then connected; and (3) possibly other layers formed like thefirst layer (element (2) above), each by means of a single steel wirewound around the core and the layer or layers which have already beenapplied. Braided bead wires obviously have a substantially circularcross section. They can be compared with a cable forming a closed loop,with the difference, however, that each layer is composed of a singlecontinuous steel wire and not of a plurality of wires.

Package bead wires are obtained from a steel wire which is wound in sucha manner as to form a large number of substantially circular turnsadjoining each other which form successive layers. These bead wires havea cross section of any shape, for instance the shape of a rectangle,parallelogram, hexagon, etc. Such bead wires are obtained by winding thewire on the inside of an annular form having a cross section of suitableshape.

Thus, in braided bead wires the turns are helicoidal and interlaced andproduce a circular structure, while in package bead wires the turns arecircular and merely juxtaposed and produce a cross section of any shape.This difference in structure results, of course, in differences inproperties.

Essentially, package bead wires are practically nondeformable but,despite this rigidity, have relatively low tensile strength per unitcross sectional area of metal. Furthermore, above a certain value of thecross'sectional area of metal, the tensile strength is practically notincreased at all by increasing the number of turns (and therefore thecross sectional area of metal). On the other hand, braided bead wiresare flexible-in a manner similar to metal cables-and, despite thisflexibility, have a much better tensile strength per unit crosssectional area of metal. Their tensile strength furthermore increasescontinuously with increasing cross sectional area of metal.

The superiority of braided bead wires explains why they are preferredfor quality tires such as radial tires. However, there is one case inwhich up to now the package bead wire has been preferred: namely, radialtires intended to be used without inner tubes on rims the bead seats ofwhich form a marked angle-say l5with the axis of the rim. In this case atight wedging of the bead on the rim is necessary and braided beadwires, because of their flexibility, might cause the tire to come offthe rim under certain circumstances. However, the use of package beadwires has a twofold drawback in this case: namely, the tensile strengthis limited and the rigidity of the bead wire results in circular breaksin the head at the location of the end of the turnaround of the carcassply.

SUMMARY OF THE INVENTION An object of the present invention is toovercome the drawbacks of conventional package bead wires andconventional braided bead wires and provide a new type of beadreinforcement which rigidifies the bead, although not excessively; whichmakes it possible to increase the tensile strength of the bead asdesired by increasing the metal cross sectional area of the bead wire;which reduces or eliminates the risk of the tire coming off the rim; andwhich eliminates, reduces or delays the formation of circular cracks inthe bead at the level of the end of the turnaround of the carcass ply.

The foregoing and other objects are attained in accordance with theinvention by the provision of a tire having beads provided withinextensible steel bead wires around which the carcass ply or plies arewound.

More particularly, each bead comprises three braided bead wires ofcircular section, each tangent to the other two, the carcass ply orplies being wound around the assembly of the three bead wires.

In a preferred embodiment, in each bead the two bead wires closest tothe base of the bead are tangent to an imaginary surface which issubstantially parallel to the surface on which the base of the bead isintended to rest. Thus, if the tire is intended to be used on a rim theseats of which are inclined by an angle a-for instance l5to the axis ofthe rim, the bead wires closest to the base of the bead are tangent to acone half the vertex angle of which is equal to a (or close to a) andthe axis of which coincides with the axis of the tire. Similarly, if thetire is intended to be used on a flat rim, the bead wires closest to thebase of the bead are tangent to a cylinder the axis of which coincideswith the axis of the tire.

The configuration formed by three circular bead wires which are tangentto one another in pairs is relatively nondeformable; in radial sectionthe centers of the three bead wires form a triangle, which, of course,is a nondeformable figure. The result is that three bead wires arrangedas indicated form an assembly which is definitely more rigid than theassembly formed by the same three bead wires arranged withouttriangulation and also more rigid than a single head wire or an assemblyof two bead wires using the same amount of metal.

The parallelism of the bead seat with the imaginary surface tangent tothe base of the assembly of the three bead wires furthermore favors thewedging of the bead on its seat.

The three bead wires may have radial sections of identical areas and becomposed of the same elements. However, this embodiment is not the bestone since in such an assembly each bead wire will not work in identhreebraided bead wires are made in a conventional manner, the properdimensions being selected for each of them (diameter of the crosssection, development of the bead wire). The three bead wires are thenassembled by any means (collars, winding around them of a wire, a strap,a spiral band, bonding with an adhesive, particularly by means ofrubber, etc.) so as to retain the desired geometrical configurationduring the tiremaking operations. These fasteners remain in the finishedtire but are not intended to play any role once the bead wires arecovered with rubber, surrounded by the carcass ply or plies andincorporated in the beads.

Alternatively, one can, before assembling the three bead wires inaccordance with the invention, cover one or more of them with a layer ofrubber. However, it is preferable that the bead wires contact each othervia their individual metal wires.

One can also use an assembly of more than three braided bead wires.However, a priori, no advantage in this arrangement can be noted.

On the other hand, one can use an assembly of two bead wires, tangent toeach other and to a conical surface parallel to the bead seat. In thiscase the third bead wire can be replaced by a bead wire consisting of aring or an annular ferrule preferably of rigid material (hard rubber,plastic, etc.). However, this embodiment provides only a part of theadvantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWING An understanding of other aspects ofthe invention can be gained from a consideration of the followingdetailed description of several representative embodiments thereof inconjunction with the appended figures of the drawing, wherein:

FIGS. I3 and 6A, 6B and 6C are fragmentary radial sectional views of thebead portions of several embodiments of a tubeless tire in accordancewith the invention;

FIG. 4 is a perspective view, partially broken away of a braided beadwire of the type used in the tires of FIGS. 1-3;

FIG. 5 is a radial sectional view on a small scale of a tire inaccordance with the invention mounted on a wheel; and

FIG. SA is a partly broken away elevational view of the tire of FIG. 5,on a still smaller scale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. l-3 show a bead ll of atire of size 11 X 22.5 comprising a carcass ply 2 the wires of which arearranged radially (see also FIG. 5A) and on one side extend at 4 intothe sidewall and on the other side stop at 5 in the bead. The bead alsocomprises a stiffener 6.

The base 7 of the bead is inclined to the axis of the tire whosedirection is indicated by the line X-X'.

The bead comprises an assembly of three braided bead wires 10, 11, 12which are tangent in pairs: i.e., each is tangent to the other two. Thebead wires 10 and 11 closest to the base of the bead are tangent to aconical surface the intersection of which with the plane of the figureis indicated by the lineL-L. The angle between the lines L-L' and X-X is15.

In FIG. 1 the three bead wires have an identical structure and comprise:

a mild steel core made of a steel wire 20 of a diameter of 2.15 mm,

a first layer of eight steel wires 21 of a diameter of a second layer oftwelve steel wires 22 of a diameter of 1.55 mm.

The interior developments or interior circumferential lengths of thethree wires 10, 11 and 12 (that is to say, the circumferences of theinternally tangent cylinders centered on the tire axis) are 1,788, 1,801and 1,836 mm, respectively, the diameter of each wire being about 8 mm.FIG. 4 shows the respective arrangement of the core 20 and of the wires21 and 22. As has been explained, each of the eight wires 21 and of the12 wires 22 is actually a portion of one and the same continuous wirethe ends of which are connected at 24 and 25 by means of a crimped-onsleeve. The wires 21 and 22 are wound respectively in the Z-directionand the S-direction.

FIG. 2 shows a slightly different arrangement of the braided bead wires10, 11 and 12. The head wire 10 has a diameter of 10.2 mm, while thebead wires 11 and 12 have identical structures and a diameter of 6.1 mm.

The bead wire 10 comprises a core 20 of a diameter of 2.15 mm and threelayers of eight, 14 and 19 wires, respectively, of a diameter of 1.30mm.

The bead wires 11 and 12 have a core 30 of 3 mm and a layer of ninewires 31 of 1.55 mm diameter.

The inner developments of the three bead wires l0, l1 and 12 are again1,788, 1,801 and 1,836 mm, respectively.

FIG. 3 shows an arrangement of braided bead wires 10, 11 and 12, allthree of different cross section.

The head wire 10 comprises a core 35 of 3 mm diameter and three layersof wires 36 of 1.55 mm diameter, numbering eight, 14 and 20 in thesuccessive layers. The diameter of the bead wire is 12.1 mm.

The bead wire 11 comprises a core 37 of 2.15 mm and a layer of eightwires 38 of 1.30 mm. The diameter of the bead wire is 4.8 mm.

The bead wire 12 comprises a core 39 of 1.55 mm and a layer of sevenwires 40 of 1 mm. Its diameter is 3.5 mm.

The inner developments of the three bead wires 10, 11 and 12 are 1,788,1,801 and 1,830 mm, respectively.

The three examples given all use an assembly of three bead wirescomprising practically the same amount of metal, this amount being 22percent less than that used on package wires.

Despite this substantial decrease in weight, the assembly of FIG. 2gives a tensile strength equal to that of the package bead wires. Theassemblies of FIGS. 1 and 3 show a decrease in the tensile strength ofthe order of only 10 percent, despite a decrease in the quantity ofmetal of more than 20 percent.

Truck tires of size 11 X 22.5 X T comprising in their beads triangulatedbraided bead wires in accordance with the examples shown in thedrawings, mounted on rims with bead seats inclined 15, have manyadvantages: they are secured on their rims better than tires withpackage bead wires or single braided bead wires; they do not showcircular cracks at the place of the turnaround of the carcass. Thetriangulated braided bead wire constitutes an excellent compromisebetween rigidity and mobility.

A tire 50 whose beads l are formed in accordance with the invention isshown in FIG. 5. It is mounted on a wheel whose rim 51 has two seats 52inclined by an angle or equal to 15 to the axis of the wheel thedirection of which is indicated by the line X-X.

FIGS. 6A, 6B and 6C show, respectively, the substitution of hard rubberor plastic bead wires 10', 11, and 12 for the bead wires 10, 11, and 12.

Thus there is provided in accordance with the invention a novel andhighly-effective tire making tubeless radial tires well adapted for useon trucks. Many embodiments of tires within the spirit and scope of theinvention will readily occur to those skilled in the art upon study ofthe present disclosure. Accordingly, the invention is to be construed asincluding all of the embodiments within the scope of the appendedclaims.

I claim:

1. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three bead wires in each bead, an end of said carcassply being wound around each assembly of head wires, at least two of thethree bead wires in each bead being made of steel, of braidedconstruction, and of circular cross section, and each of the three beadwires in each bead being tangent to the other two.

2. A tubeless tire according to claim 1 wherein two of said bead wiresin each bead adjacent to the base of the bead are tangent to animaginary surface substantially parallel to the surface on which thebase of the bead is intended to rest.

3. A tubeless tire according to claim 1 wherein two of said bead wiresin each bead adjacent to the base of the bead are tangent to animaginary conical surface whose axis coincides with the axis of the tireand the half-angle of the vertex of which is substantially 15.

4. A tubeless tire according to claim 1 wherein each of said three beadwires in each head is of the same structure and cross section.

5. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three substantially inextensible steel bead wires ineach bead, an end of said carcass ply being wound around each assemblyof bead wires, each of the three bead wires in each bead being braided,of circular cross section, and tangent to the other two, two of saidthree bead wires in each bead being of the same structure and crosssection and the third bead wire in each bead having a larger crosssection.

6. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three substantially inextensible steel bead wires ineach bead, an end of said carcass ply being wound around each assemblyof bead wires, each of the three bead wires in each bead being braided,of circular cross section, and tangent to the other two, and each ofsaid three bead wires in each bead having a structure and cross sectiondifferent from those of the other two bead wires in the same bead.

7. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three substantially inextensible steel bead wires ineach bead, an end of said carcass ply being wound around each assemblyof bead wires, each of the three bead wires in each bead being braided,of circular cross section, and tangent to the other two, and each ofsaid three bead wires in each bead having a structure and cross sectiondifferent from those of the other two bead wires in the same bead, thecross section of each bead wire in each bead being proportional to theforce which it withstands.

8. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three bead wires in each bead, an end of said carcassply being wrapped around each assembly of bead wires, two bead wires ineach head being made of steel and being braided and of circular crosssection, the third bead wire in each bead being formed of a rigid,nonmetallic material, and two of said bead wires in each bead adjacentto the base of the bead being tangent to an imaginary surfacesubstantially parallel to the surface on which the base of the head isintended to rest.

9. A tubeless tire according to claim 8 wherein said rigid, nonmetallicmaterial is hard rubber.

It}. A tubeless tire according to claim 8 wherein said rigid,nonmetallic material is plastic.

* a a: a: e

1. A tubeless tire comprising a pair of beads, at least one carcass ply,and an assembly of three bead wires in each bEad, an end of said carcassply being wound around each assembly of bead wires, at least two of thethree bead wires in each bead being made of steel, of braidedconstruction, and of circular cross section, and each of the three beadwires in each bead being tangent to the other two.
 2. A tubeless tireaccording to claim 1 wherein two of said bead wires in each beadadjacent to the base of the bead are tangent to an imaginary surfacesubstantially parallel to the surface on which the base of the bead isintended to rest.
 3. A tubeless tire according to claim 1 wherein two ofsaid bead wires in each bead adjacent to the base of the bead aretangent to an imaginary conical surface whose axis coincides with theaxis of the tire and the half-angle of the vertex of which issubstantially 15*.
 4. A tubeless tire according to claim 1 wherein eachof said three bead wires in each bead is of the same structure and crosssection.
 5. A tubeless tire comprising a pair of beads, at least onecarcass ply, and an assembly of three substantially inextensible steelbead wires in each bead, an end of said carcass ply being wound aroundeach assembly of bead wires, each of the three bead wires in each beadbeing braided, of circular cross section, and tangent to the other two,two of said three bead wires in each bead being of the same structureand cross section and the third bead wire in each bead having a largercross section.
 6. A tubeless tire comprising a pair of beads, at leastone carcass ply, and an assembly of three substantially inextensiblesteel bead wires in each bead, an end of said carcass ply being woundaround each assembly of bead wires, each of the three bead wires in eachbead being braided, of circular cross section, and tangent to the othertwo, and each of said three bead wires in each bead having a structureand cross section different from those of the other two bead wires inthe same bead.
 7. A tubeless tire comprising a pair of beads, at leastone carcass ply, and an assembly of three substantially inextensiblesteel bead wires in each bead, an end of said carcass ply being woundaround each assembly of bead wires, each of the three bead wires in eachbead being braided, of circular cross section, and tangent to the othertwo, and each of said three bead wires in each bead having a structureand cross section different from those of the other two bead wires inthe same bead, the cross section of each bead wire in each bead beingproportional to the force which it withstands.
 8. A tubeless tirecomprising a pair of beads, at least one carcass ply, and an assembly ofthree bead wires in each bead, an end of said carcass ply being wrappedaround each assembly of bead wires, two bead wires in each bead beingmade of steel and being braided and of circular cross section, the thirdbead wire in each bead being formed of a rigid, nonmetallic material,and two of said bead wires in each bead adjacent to the base of the beadbeing tangent to an imaginary surface substantially parallel to thesurface on which the base of the bead is intended to rest.
 9. A tubelesstire according to claim 8 wherein said rigid, nonmetallic material ishard rubber.
 10. A tubeless tire according to claim 8 wherein saidrigid, nonmetallic material is plastic.